Motion compensated temporal filters (MCTF) are used in pixel processing of video images. MCTF is an adaptive temporal filter along estimated motion trajectories. The temporal correlation is exploited through temporal filtering. MCTF is most effective in processing sequences of images in which signal is highly temporal correlated along the motion trajectories but the noise, by nature, is totally uncorrelated. In other words, the image does not change from frame to frame but the noise does. The noise probability distribution is also exploited. MCTF is primarily used to reduce the zero mean stationary white Gaussian noise. Such noise has a bell shaped distribution, and it is of primarily small magnitude. Large magnitude noise rarely happens. Based on these two observations, the magnitude differences between the current frame and the previous filtered frame are first calculated along the estimated motion trajectories. Small differences are considered primarily of noise. Large differences are considered primarily of signal content.
However, existing MCTFs do not remove all of the noise inherent in a video signal, thereby wasting valuable bandwidth resources.
The present invention is therefore directed to the problem of developing a method and apparatus for performing filtering of noise in a video encoding process that removes as much of the noise as possible without disrupting the video image.